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Using SHEDS-S/D to Estimate Soil and Dust Ingestion Rates for Children
Citation:
Glen, G., H. Ozkaynak, H. Hubbard, J. Cohen, N. Tulve, L. Phillips, K. Thomas, AND J. Moya. Using SHEDS-S/D to Estimate Soil and Dust Ingestion Rates for Children. 2017 ISES Annual Meeting, NC, Durham, October 15 - 19, 2017.
Impact/Purpose:
Presented at the 2017 ISES Annual Meeting
Description:
Soil and dust ingestion can be the primary pathway for environmental exposure to some pollutants. Studies have shown that young children, due to their greater mouthing behavior than older children or adults, are more vulnerable to incidental ingestion of soil and dust. However, available data to support the development of age-specific soil and dust ingestion rates are either limited or uncertain for most age groups. Our objective was to use the Stochastic Human Exposure and Dose Simulation Soil and Dust (SHEDS-S/D) model to estimate distributions of soil and dust ingestion rates for infants and children to determine if data gaps could be filled using this modeling approach. We developed a new exposure scenario in SHEDS-S/D to capture exposures to indoor dust via pacifier use by infants and very young children. This exposure scenario accounts for the use of blankets or similar surfaces that may prevent direct contact of the pacifier with the floor. Although the inputs for this scenario were uncertain, the scenario was estimated to contribute approximately 20 mg/day to overall dust ingestion. We also conducted a sensitivity analysis by age group to determine key drivers of exposure. For infants and younger children, pacifier use drove exposure with the most sensitive variables being carpet dust loading, pacifier drop frequency, and the floor-to-pacifier transfer fraction. For older children, key variables were carpet dust loading, soil adherence, four hand properties, the frequency of hand-to-mouth contact, the area of the hand mouthed, the amount of floor contacted by the hand, and the fraction of dust removed by each hand-to-mouth event. These results can be used to identify data limitations in developing robust soil and dust ingestion rates and to focus resources on the variables that will provide the most insight in developing age-specific rates, as well as describing differences in ingestion rates within and between populations.
